Generally, liquid crystal displays, advertising displays, guide signs, and the like are not self-luminous display devices having display units that emit light by their selves. Therefore, it is necessary to provide planar light source devices such as backlights at the rear faces of the display units. The planar light source devices are a side light type (also referred to as an edge light type) and a direct back light type, for example. In the side light type of planar light source devices, light sources are disposed on side portions of cases, and in the direct back light type of planar light source devices, light sources are disposed on the rear face sides of cases to face the liquid crystal display unit.
The side-light-type planar light source devices may use light guide plates for guiding light from light sources in desired directions. The planar light source devices using the light guide plates may use line light sources such as cold cathode fluorescent lamps, or a circuit board such as a Flexible Printed Circuit board (hereinafter, referred to as FPC) having point light sources such as light emitting diodes arranged in line thereon. The FPC includes wiring patterns for supplying electric power to each of the point light sources such as LEDs, and has connectors at their end portions. The connectors are connected to other connectors of drivers or the like for supplying electric power to the FPC, and electric power is supplied to each of the point light sources through the wiring patterns. Incidentally, if an FPC shifts, a defect may occur in the connection between the connector of the FPC and a corresponding connector.
For this reason, JP-A-2007-78929 discloses an electro-optical device having a structure for position connectors by an extending portion of a FPC and an positioning reference portion provided at a portion of a case. Therefore, a defect in the connection between the connectors is suppressed.
Also, JP-A-2005-267881 discloses a planar light source device having a structure for inserting a second FPC having light sources mounted thereon into a notched portion of a frame. Therefore, the second FPC is locked at an appropriate position.